Process of producing pigmented paper and impregnating it with a resinous binder and the product



2,125,076.v PROCESS OF PRODUCING PIGMENTED PAPER AND IMPREGNATING IT G. H. MAINS July 26, 1938.

WITH A RESINOUS BINDER AND THE PRODUCT Filed Dec. 12, 1933 75 power {auras Hyman/ea 10720;? 5196497? d. M a 5 M w e a 3; h b W 5,; Z Z Z B Z m MM M m .w

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WITNESSES Patented July 26,- 1938 PATENT OFFICE PROCESS OF PRODUCING PIGMENTED PAPER AND IMPREGNATING IT WITH A RESINOUS BINDER, AND THE PRODUCT Gerald B. Mains, Murrysville, Pa assignor to Westinghouse Electric 6: Manufacturing Company, East Pittsburgh, Pa a corporation or i Pennsylvania Application December 12, 1933, Serial No. 702,022

The invention relates generally to a process for making pigmented fibrous sheets impregnated with a resinous binder and utilizing these sheets to. make colored or ornamented molded products.

In the manufacture of molded products when phenolic resins are employed as the hinder, the article produced is likely to have a yellowish or straw colored tint. Such tints are generally undesirable and render the article less appealing no to the trade.

Many processes for producing impregnated pig mented fibrous sheets and laminated products of predetermined colors or presenting selected designs and colors have been tried, but heretow fore great 'difliculty has been experienced in producing a satisfactory product or employing these processes on a. commercial manufacturing scale. For example, the treating of paper sheets with pigmented phenolic resins or varnishes to give a desired color and render them opaque to adapt them ior use as surface or sub-surface sheets in laminated products cannot be carried out with any great degree of success because the high viscosity of the pigmented resins make 25 it diflicult to obtain a uniform impregnation and coating of the sheets. when such a process is employed the surfaces of the paper are merely coated but the body is not thoroughly impregnated. Attempts to impregnate pigmented paper such as Mom in the printing trades with a 'ed sheets are hard and non-porous and the resins do not penetrate them. When sheets prepared in accordance with these processes are as employed to make laminated molded products,

the surface coats of the resinous binders will unite with the next adjacent sheets when subjected to heat and pressure, but as soon as the pressure is relieved, the coated sheet is liable to split along a central plane parallel with the sur- Whenpigmented phenolic resins are employed for treating sheetait is very 'diflicult to keep the resin solutions in proper condition for-car- 45 rying on the process because of theirtendency eral steps and the relation and order of one or more 01' such steps with respect to each of the 55 others, and the article possessing the features,

resinous binder have failed because the pigmentiace planes. This is sometimes called blistering.-

ment into the heater to be mixed with the paper stock during the beating. operation.

Fig. 2 is a view in side elevation of an ex-' ploded stack oi, pigmented imprwnated sheets prepared and arranged in accordance with this invention. I

Fig. 3 is a view similar to Fig. 2 with a difi'erent arrangement of pigmented impregnated sheets. a

Fig. 4 is a view in side elevation of pigmented impregnated sheets as they would be arranged for molding with non-adhesive bodies or bodies i of molding compositions of fibrous materials and synthetic resins, and

Fig. 5 is a diagrammatic view of pressing plates suitable for molding the stacks of sheets illustrated in Figs. 2 to i, inclusive.

in the present invention, a plurality of sheets oi any suitable fabric or paper are impregnated with a phenolic, urea or other resin that may be readily molded. -These sheets are superimposed on one another to form a hody stack of the desired mm.

In order to prevent the body sheets from giving the final product a tint, an opaque sheet may be employed. This opaq e sheet may he utilized as a surface sheet or sub-surface sheet, the uses of which will be explained hereinafter.

In this embodiment of the invention, the opaque sheet employed for a surface or subsurface sheet is produced by intimately mixing a predetermined amount of an inorganic pigment of a desired color with paper stock or pulp duringthe beating operation in the paper making process. The quantity of pigment dispersed throughout the paper will depend on the conditions to he'met in the final product.

The quantity of pigment that will be used will depend on the character of the raw materials 'employed, the length of time the heating process is continued and the porosity required to enable the pigmented paper to absorb a predetermined amount of the resinous binder during the impregnating process.

It has been found that for most purposes, to 20% by weight of a pigment, such as titanium oxide, is sufiicient to mix with stock during the beating operation in-the paper making process to render a sheet approximately 5 mils thick opaque and to maintain sufllcient pogives the paper a yellow color.

. rosity or capacity for absorbing a resinous binder.

It is to be understood that these'quantities of inorganic pigments are not the limits because 2% by weight of a pigment has been found very serviceable for many purposes. The proportion of pigment required to obtain desired opacity will vary with the thickness of the paper.

The pigmented sheets will be impregnated with some suitable binder such as urea. phenolic, vinyl, or sugar type resin to adapt them for molding. The quantity of resin embodied in the sheet will depend on the conditions to be met.

When it is desired to produce a molded laminated product of a predetermined color, an opaque sheet embodying the proper pigment to give it the desired color may be utilized as the finishing or surface sheet. If it is desired to fluish the molded laminated product to present a figure or design, this figure or design may be printed directly on the pigmented sheet.

The pigment employed will depend on the color it is desired to produce. If a white opaque sheet is required, some suitable white pigment such as titanium oxide having a high covering capacity will be introduced into the paper stock during the beating process. other pigments that have been utilized with success are oxides of iron, which produce a'reddish color, chromium oxide, which renders the sheet green, and oxide of lead, which Certain chromates and other salts which will not decompose under the molding temperature may also be utilized as pigments. -By proper combinations of these inorganic pigments and introducing them into the paper stock during the beatingprocess, many different colors may be produced. In order to secure a wide variety of tints in the final product, dyes and pigments may be mixed into the pulp during the heating process.

- quent exposure to light.

In making certain finishing or surface sheets good results are obtained by employing such a small percentage of pigment that the sheet will be semi-translucent. Asheet having a low pig'- tint after molding.

Referring now-to Figs. 1 to 3, inclusive, the sheets of paper ID are impregnated with a phenolic or urea resin in order to adapt them to be molded mm? unitary structure. The selection of the resin for the binder will depend on the requirements of thej'flnal product.

The, opaque colored sheet ismade by introducing-spine suitable pigment H into the beater I2 01' the"paper making machine I! to mix it with the pulp or stock. By introducing a predetermined amount of pigment into the stock and operating the heater for a predetermined time, they will be so intimately and thoro hly mixed that sheets made from the mixture will be opaque and of the desired color.

In the making of a white opaque sheet from alpha cellulose, from 10% to 20% by weight of titanium oxide may be added to the stock during the heating process. It has been found that when this quantity of titanium oxide is employed the paper will remain sumciently porous to receive enough of a resinous binder to adapt the sheet for molding. The pigmented sheet will ordinarily be impregnated with the same resinous binder as the body sheets, but this practice is not always required.

When it is desired to produce amolded product of a predetermined color, an opaque colored sheet I5 is superimposed on the sheets l0, and the stack is subjected to heat and pressure between the heated pressing plates of a press l6 until it is molded into a single mass or unitary structure of a predetermined size and shape.

In case it is desired to produce an article presenting a design, a transparent or-translucent sheet of paper ll having the design printed thereon is impregnated with the same resinous binder as the opaque sheet. This sheet I1 is then superimposed on the opaque sheet l5, which may be made of any desired color-and the two placed on the stack of sheets Ill. The whole stack of sheets is then molded into the desired product in the press I6. I

In some cases the design may be printed on the opaque sheet. In this manner, a'design backed by a sheet having a desired color may be ,produced readily.

In many cases it may be desirable to provide surface sheets. l5 and opaque sheets I! on both sides the stack. However, this will be a matter of arrangement which will be decided by the manufacturer.

The applications of pigmented impregnated sheets are not to be limited to use in combination with sheets impregnated with resinous binders. Pigmented impregnated sheets l5 may as readily .be molded to non-adhesive bodies l8, such as metals, woods, asbestos sheets and composite fibrous boards and to bodies such as molding compositions of fibrous materials and synthetic resins. The sheet will be arranged as shown in Fig. 4; In all cases, the pigmented impregnated sheets may be employed in finishing the article being manufactured. In some instances the pigmented impregnated sheets may be applied to give a desired finish to the article, while in others to increase its durability. I

In addition to the above uses, pigmented sheets 11" properly impregnated because of their fast colors and resistance to water and chemical action will meet many of the demands for opaque 'and colored sheets that arise in the packaging and decorating 'arts. In the building industry, sheets prepared in accordance with the teachlugs 01' this invention may be utilized for decorative panels and ior many other purposes.

Themolding of the sheets between pressing plates I! of the press l6 may be performed by applying heat and pressure in accordance with practices well known in the art, and an explanation-ot the details will not be given.

Since certain changes in carrying out the above process and certain modifications in the article which embody the invention may be made without departing from its scope, it is intended that all matter containedin the above description or shown in the accompanying drawing shall'be inalarms I claim as my invention:

i. A molded laminated product comprising a s plurality of sheets of paperimpregnated with of sheets of paper impregnated with a synthetic a resinous binder suitable for molding, a sheet of paper having a pigment dispersed throughout the body thereof and impregnated with a resinous binder superimposed on the other sheets. all of i the sheets being molded into a unitary structure. 2. A. molded laminated product comprising a pmmuty of sheetsof paper impregnated with.

a resinous binder suitable for molding, a subsurface sheet of paper having a pigment disis persed throughout the body thereof and impregmated with a resinous binder, and a sari ace sheet.

of paper impregnated with a. resinous binder superimposed on the sub-surface sheet, all of the sheets being molded into a unitary smicture.

3. A molded laminated product comprising a "plurality of sheets 'of paper a synthetic resinous binder, a sub-surface sheet I of paper having a pigment dispersed throughout the body thereof and impregnated with a 2 synthetic resinous varnish superimposed on the other sheets, a surfacesheet of paper impreghated with'a resinous varnish'superimposed on the sub-surfacesheet, all ofthe sheets being molded into a unitary structure. I0 4; A molded laminated product comprising a plurality of sheets of paper impregnated with a urea resin suitable for molding, a surface sheet of paper having a pigment dispersed thro shmlt the body thereof which-renders it opaque and 1 ll gives it a predetermined color impregnated with urea-resin, allvofthesbeets being molded into aunitary-structure.'-

5. A molded laminated productcomprlsing a pmralityofsheetsofp p impr sn witha on the'other sheets, and a surface sheet w natedwith urearesin w -1 onthesuhsurface sheet, all of the sheets w i molded into a unitary structure.

6. A laminated product comprising a plurality d binder to form a body, a sheet of paper haying a pigment of a'predetermined color dispersed throughout the body thereof rendering it opaque, said pigmented sheet being impregnated with a 30 resinous binder and a i t 1 sheet of paper embodying pigment of a prede'color,

said g sheet being impted with a resinous hinder. r t

'l. A molded laated product comprising a id plurality of sheets of celiulo'sic material impregnoted with a resinous binder suitable for molding a sheet of celiulosic paper having 9. out dispersed throughout its the quantity of pigment beingso selected that the paper retains a at predetermined porosity, said piented porous sheet being impregnated with a resinous binder and superimposed on the other sheets, all of the sheets being molded intoa unitary sh'uctin'e.

8. In the manufacture of composite molded as sheet materials having a decorated surface on an opaque-background, the features of decorating a papersheet, containing plsment homogeneously distributed between its fibers with a design, treating it'with a binder con- .80 solidatingthe resultant decorated surface sheet with a support by a hotmolding operation.

9. A composite, molded sheet material bearing a decorated opaque binder impregnated surface 88 sheet containing a pigment husly distributed betweentlie fibers, which has been produced' by decorating a paper sheet containing pigment homogeneously distributed between its iiberswitha-Jreatingi withabinder" andfinaily-consolidating the tant decorated surfacemeet lywithpm byahotmoldinsop i'stion. 

